Agrium CEO Mike Wilson told CNBC's Squawk on the Street Tuesday that criticism from activist hedge fund Jana Partners, which has called for a breakup of the Canadian fertilizer company, "has no legs."

"We've given close to 500% shareholder value since 2005, we are outpacing our competition and the shares are up," Wilson said, "When the company is performing extremely well and is ahead of the competition, why would you want to split it up? Our stock is up because our retail (earnings) went up and Jana had nothing to do with it."

"We have huge operating synergies," Wilson said, citing the impending deal to purchase the farm retail business from Glencore's Viterra division. Wilson said that the Viterra deal "was just a gold mine for us."

Agrium is a global producer and marketer of nutrients for agricultural and industrial markets with a market cap of $17 billion. The company operates three divisions - retail, wholesale and advanced technologies - which Jana has said could be split up to unlock value from the firm.

Dave Olecko | Bloomberg | Getty Images

Agrium headquarters in Calgary, Alberta, Canada.

New York-based Jana is Agrium's largest shareholder, holding 6% of the company's outstanding shares. The hedge fund also has been pushing for a reshuffling of the company's board to include five new directors. This move was originally proposed in November.

The hedge fund said it wants directors on Agrium's board with more "relevant distribution experience" and blames the current board for what it sees as "historical share price underperformance."

Jana also said that it wants Agrium to improve cost controls and disclosures to shareholders as well as make a more efficient use of its capital. Jana's position and full analysis is available online here.

The company also maintains that its recent share buyback and dividend boost are unrelated to the situation with the activist shareholder, and told Reuters that "Jana's best decision was buying our stock."